Rack and pinion steering gear

ABSTRACT

A rack and pinion steering gear for automotive vehicles and the like includes a relatively short pinion housing, an elongated rack guide tube received within a somewhat overlarge longitudinal bore of the pinion housing and which in turn receives a reciprocable rack member meshingly engaged by a pinion on a pinion shaft mounted in a cross bore of the pinion housing, with the rack guide tube being adjustable positionally within the overlarge housing bore in directions radially, axially and tiltably therewithin to effect proper sdjustments of the mesh of the rack and pinion and the preload therebetween.

[ Jan. 29, 1974 RACK AND PINION STEERING GEAR [75] Inventor: Ernest M.Plant, II, Frankenmuth,

Mich.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[22] Filed: Oct. 30, 1972 [2]] Appl. No.: 301,869

[56] References Cited UNITED STATES PATENTS 11/1967 Adams 74/388 PS 1 l/l97l Bradshaw et al. r. 74/498 Primary ExaminerLeonard H. Gerin A e A et o Firm 1 Ellis [5 7] ABSTRACT A rack and pinion steering gear forautomotive vehicles and the like includes a relatively short pinionhousing, an elongated rack guide tube received within a somewhatoverlarge longitudinal bore of the pinion housing and which in turnreceives a reciprocable rack member meshingly'engaged by a pinion on apinion shaft mounted in a cross bore of the pinion housing, with therack guide tube being adjustable positionally within the overlargehousing bore in directions radially, axially and tiltably therewithin toeffect proper sdjustments of the mesh of the rack and pinion and thepreload therebetween.

8 Claims, 4 Drawing Figures PATENTED JAN 29 1974 SHEET 1 BF 2 PATENTEI]JAN 2 9 I974 SHEET 2 BF 2 RACK AND PI'NION STEERING GEAR This inventionrelates to steering gears and more particularly to an improved-rack andpinion type of steering gear for automotive vehicles.

The principal feature of this invention is that it provides an improvedrack andpinion steering gear for automotive vehicles and the likeembodying structural features adapted to an economical yet precisionadjustment of proper meshing engagement between the rack and pinionparts thereof during assembly.

Another feature of the invention is that the foregoing is accomplishedwith the aid of in situ injection molding of retaining structure betweenadjustable parts of the rack and pinion gear.

In its more specific aspects, the invention features the provision of apinion housing of relatively short length fitted with a rack guide tubereceivablein a somewhat overlarge longitudinal bore of the pinionhousing, the rack guide tube being adjustable in relationship to thehousing in directions axially, radially and tiltably within the latterso as to effect proper mesh of the rack and pinion as well as properpreload therebetween and proper location of the movable parts of thegear in a centered condition affording generally precisely equal travelof such parts in either direction from centeredcondition.

The foregoing and other features and advantages of the invention will bereadily apparent from the following specification and from the drawingswherein:

FIG. 1 is a partially broken away plan view of a rack and pinionsteering gear assembly according to this invention; 4

' FIG. 2 is a sectional view taken generally along the plane indicatedby lines 2-2 of FIG. 1;

FIG. 3 is a view similar to FIG. 1 showing a modification of theinvention adapted to fluid power operation; and

FIG. 4 is an enlarged sectional view taken generally along the planeindicated by lines 44 of FIG. 3

Referring particularly to FIGS. 1 and 2 of the drawings, illustratedthere is a manual version of a rack and pinion steering gear assemblyaccording to this invention and indicated generally by the referencenumeral I 10. The gear assembly includes a pinion housing 12 of forged,cast or like construction and of a relatively short configuration.Defined within housing 12 is a longitudinal rack bore 14 and, in a planeorthogonal to the plane of the rack bore 14, a cross bore 16 having itsaxis elevated with respect to the axis of rack bore 14 and necessitatinga humped portion 18 in the gear pinion housing .12. Integral bosses suchas at 20 are provided for boring and tapping therein to receive threadedfasteners for attachment of the housing 12 to the vehicle frame orotherwise,

A rack guide tube of elongated configuration, indicated at 22, isreceived within and extends completely through rackv bore 14. Asindicated in the drawings, the diameter of rack bore 14 is somewhatenlarged with respect to the selected outer diameter of tube 22 forreasons that will later appear. As indicated in FIG. 2, a relief orcutout 24 is provided in the wall of tube 22 in the region thereofadjacent the cross bore 16 for reception of a pinion and pinion shaftassembly. A rack 26 is received for relatively free sliding movementwithin the tube 22, such rack member including a set of rack teeth 28 ofthe helical variety. Bushings 30 and 32 are received at either end ofrack tube 22 and support the rack therewithin for sliding movementwithout substantial friction. These bushings may be fabricated ofasuitable tough plastic material such as Teflon-impregnated Delrin. Thebushings are fabricated in a special reentrantly annularly foldedconfiguration so as to snapfittingly engage and retain itself onserrations 34 on the terminal ends of tube 22, like serrations beingformed on the inside wall of the outer annulus of each bushing 30 and32. A bumper ring 36, again ofa durable plastic material or the like, issqueezed over the end of each bushing 30 and 32.

The gear assembly 10 further comprises a pinion and pinion shaftsubassembly 38 within cross bore 16 and which includes a pinion 40adapted for proper meshing engagement of its helical teeth 42 withrackteeth 28. The pinion is preferably formed integrally with reduceddiameter shaft ends or shanks either side thereof constituting a singleshaft. Referring to the broken lines and the partially broken awayportion of FIG. 1, there is located adjacent either end of such pinion40 a pinion bushing 44 received in enlarged counterbores 46 of humpedportion 18 of the pinion housing and which in turn journal the reduceddiameter shaft end portion of the shaft upon which pinion 40 is formed.Again, such bushings may be fabricated from one of the tough plasticpolymeric materials. A splined input end 48 of such shaft extends fromone end of the cross bore 16 for suitable connection with a steeringcolumn steering shaft or other manually rotatable element aswell-understood in the art. A conventional snap ring 50 retains theadjacent one of the bushings 44 within humped portion 18 against ashoulder of its counterbore 46. Adjacent the other bushing 44, a pair ofhardened steel races or washters 52 are interposed over the reduceddiameter shaft end between pinion 40.and such bushing, and the terminalend of such shaft end indicated at 54 is threaded to be received withina like-internallythreaded cap 56 which has an annular flange 58 bearingagainst a further hardened race or washer 60 abutting with the otherside of the adjacent bushing 44. Thus, suitable threading adjustment ofcap 56 will thrust-load this pinion and pinion shaft element againstthis bushing eliminating end play. A roll pin 61 is inserted withinaligned bores of the cap and such shaft end in conventional manner tohold the adjustment. The bushing 44, in turn, is abutted against anannular shoulder 62 of humped portion 18 at counterbore 46 under thepressure of a retention sleeve 64 borne at its other end by a cover 66over cross bore 16 bolted to a flange 68 of the humped portion 18.

A flat or blade type of preload spring 70 is located within a channel 72of humped portion 18, and, as seen in FIG. 1, bears at its two endsagainst sides of the bushings 44. As indicated in FlG.'2, and perhapsmore clearly in FIG. 4 in connection with another similar gear assembly,spring 70 is bowed convexedly to seat generally midway its length firmlyagainst housing 12 and room is permitted for flexure of such spring atits ends about its midportion to stress the spring as a result ofradially displacing the bushings in the overlargesized counterbores 46.This is achieved by, as viewed in FIG. 2, bodily vertically displacementof the meshed rack and pinion subassembly, along with rack tube 22 inthe rack bore 14, until a desired amount of radial force or preload ispresent between rack teeth 28 and pinion teeth 42.

Referring now most particularly to FIG. 2, as there indicated, thisvertical preloading displacement, in connection with one feature, isachieved by making longitudinal rack bore 14 of housing 12predeterminedly larger in diameter than the outer diameter of tube 22.The predetermined difference therebetween is selected with reference tothe amount (a) of radial displacement required to achieve preloadingpressure of desired value in spring 70 and between teeth 28 and 42, and(b) the amount of tiltable adjustment which may be necessary toperfectly align the flanks of the rack teeth 28 with those of pinionteeth 42. The radial displacement of the pinion subassembly 38 as by theupward displacement of the rack previously described is believedapparent. It replaces more costly and complex methods of tooth preloadsuch as by adjustable threaded plugs between the rack and rack housingwith or without springs. The tiltable adjustment referred to is thatadjustment indicated with reference to FIG. 1, wherein, assuming an axisof the longitudinal rack bore 14 indicated by A, some slight angularmisalignment between it and the axis of rack 26, indicated at B, isnecessary to achieve flush or uniform engagement of the flanks of thehelical teeth 42 and 28 of the pinion and rack. Such need formisalignment can very often be the case due to the expected variations,as in lead angle or tooth helix, that can occur in the fabrication ofthe pinion and rack as separate parts on separate machinery. Thus, wheresuch variations are present, it can be readily accommodated by atiltable or skewing adjustment between the symmetrical planes of therack tube 22 and of rack 26 through its teeth to some angle such asindicated at 6 in FIG. 1.

In the case of a present constructed embodiment of the illustrated gearassembly 10, where the outer diameter of tube 22 is 1.25 inchesnominally, a total clearance between that and the rack bore of 0.044inches will accomplish the required range of radial and tiltableadjustment indicated. The radial adjustment is, of course, dependent onthe rate of the spring 70 and the amount of wear between the teeth ofthe parts and in the bushings 32 expected to occur over a period of use.

Once having accomplished the desired adjustments mentioned above, theymay be held by in situ injection molding of retaining structure betweenthe housing 12 and the rack guide tube 22. As seen best in FIG. 2,housing 12 is provided adjacent either end with passage means includinga circumferential series of radially extending apertures 74 opening toan annular groove 76 communicating with rack bore 14. Juxtaposed to suchgrooves 76 are complementary grooves 78 formed annularly within theouter surface of tube 22. .luxtaposed as they are, grooves 76 and 78form annuli or cavities extending around tube 22 which receives underinjection pressure a quantity of curable plastic material 80, such asnylon, which, when cured, form retaining rings. Thus, once having fixedthe relationship between tube 22 and housing 12 as above, injectionmolding of plastic 80 into these grooves and subsequent curing thereofas part of the manufacturing process forms an economical and highlyefficient permanent retention of the adjusted relationships mentionedsuitable for long periods of use and rugged duty. It will also beobserved that with the amount of gap present around the periphery oftube 22 inside housing 12, the passage means referred to may alsoinclude certain portions of the annular interspace therebetween. asshown, to the extent that such is allowed given the pressure ofinjection of plastic therewithin, thereby advantageously to contributeto permanent retention of the relationship of the parts. Such plasticflow into and around the interspace can be confined to regions outsidecross bore 16 by use of sealing rings 82, shown in FIG. 2. Thisinjection molding of plastic 80 may take place in a fixture constructedto hold both the housing 12 and the rack tube 22 in a selectedrelationship until plastic 80 is cured to the point of holding theforces developed in spring transferred by the pinion to the rack and therack tube.

A further important feature of this invention resides in theaccommodation of the described structural assembly to minor endwise oraxial adjustment of the relationship of tube 22 within housing 12. Thus,after a final assembly of the various parts into the configuration seenin the drawings, it may be necessary to slightly relocate, prior toinjection molding, rack tube 22 relative to the axis of the pinionshaft, this to insure that equal amounts of travel are permitted therack either side of a centered condition up to bumpers 36. The width ofthe grooves 76 and 78 permits such minor adjustment since they may bejuxtaposed with only a portion of one groove facing a portion of theother and only to the extent required for communication of plasticthereto during molding and of sufficient thickness of plastic to holdaxial forces between the parts without fracture. This may be betterunderstood with reference to a preferred assembly process sequence. Afirst step in such process may be the insertion of rack tube 22 withinbore 14. Rack 26 is then inserted within tube 22 and the rack and thetube are adjusted lengthwise of the housing, first to generally locategrooves 76 and 78 opposite one another and subsequently to adjust therack within the tube until generally equal travel is available betweeneach remote end of the rack and its respective bumper 36. If preferred,this latter need only be a coarse adjustment. The pinion subassembly 38is then next inserted in cross bore 16 including the installation ofspring 70, the thrust loading of the cap 56 and the installation of snapriding 50 and cover 66. The pinion shaft is inserted in such angularposition that the usual coupling alignment flat 480, FIG. 1, on thesplined end 48 is in a preferred vertical position. The described radialand tiltable adjustment of tube 22 is then performed to obtain precisemeshing engagement of gear teeth and preloading in spring 70 as above. Afinal check may then be made of the amount of travel either side of therough center position available to rack 26 and, if unequal, fineadjustment may be made by axial relocation of tube 22 with its bumper 36within the limits of the width or range of juxtaposition of the grooves76 and 78 and, with the adjusted parts being held in a fixture or thelike, plastic 80 may then finally be molded into the passages betweenthe parts and cured. Note will be made that cutouts 24 are purposelylarger, as seen in FIG. 2, than the diamter of the midportion of crossbore 16 to accommodate this adjustment of the tube 22 withoutinterference from pinion 40.

Referring now particularly to FIGS. 3 and 4 of the drawings, amodification of the invention adapted for fluid power operation isshown. The power rack and pinion unit, generally designated 84, includesbasically the same manual gear components as in the previous embodimentsuch being indicated generally at 86, and including the pinion housing12', the rack tube 22' and the pinion and pinion shaft subassemblyindicated at 38'. Here additionally, further showing is made of suitablerubber or like bellows or dust boots 88 which may each be secured at theouter end of rack tube 22 at one end and to the respective ends of therack 26 at the other end to prevent the entry of foreigh matter. Alsoindicated is the connection by a conventional ball joint or otherwise at90 of conventional steering linkage to the rack 26. The remote ends ofthe rack 26 are here indicated at 92 and 94 to show the rigid flange orlike structure which may be employed to abut with the bumper 36 on theend of rack tube 22.

In the case of this power operated unit, additional power components areprovided in the form of a hydraulic cylinder and piston subassembly 96having one end of the cylinder 98 attached fixedly to pinion housing 12and an opposite end of the rod portion of the piston indicated at 100 toa bracket or connector 102 affixed to the rack 26. Additionally includedis a suitable hydraulic four-way valve subassembly 104 for directingfluid pressure to either side of'the movable wall, not shown, of piston100 within cylinder 98. Valve assembly 104, best viewed in FIG. 4, is ofthe axial spool valve variety including a two-part spool valve member106 mounted slidably within the bore of valve housing 108 which isbolted or otherwise affixed to pinion housing 12. Valve member 106 isretained between a roller bearing 110 and nut 112 at one end of anactuating rod 114, and at the other side against a washer 118 bearing atits other side against a further roller bearing 120 backed up by anenlarged end 122 of rod 114. This enlarged end is coupled to rotate as aunit with the inner end of the pinion shaft.

Routing of hydraulic pressure through the valve subassembly to oppositesides of the piston 100 is of generally conventional open-centerconfiguration where incoming pressure fluid delivered from a pump or thelike via pressure passage 124 will, in the neutral condition of thevalve shown, communicate toboth sides of the piston via chamber passages126 and 128 respectively, and also back to the usual fluid sump viareturn passages 130, all indicated in broken lines. As is wellunderstood in the art, axial displacement of the valve member 106 ineither direction progressively cuts off the supply of pressure fluidfrom passage 124 to one of similar aligned shoulders on the housing andon the washer 118. Movement of the rod 114 and valve memher 106 ineither direction from the position shown will further compress spring132 from an initial preloaded compression and subsequent return of thevalve member to centered condition is thus effected when the steeringmaneuver is accomplished, all in well-known manner.

Suitable communication of the actuating fluid pressure to either side ofthe movable wall of piston 100 through passages 126 and 128 may be donewith the use of connecting pipes 138 shown in FIG. 3, or alternativelyby integrally formed passages as may be found convenient within a moreintegrated unit comprised of the piston and cylinder and the valvehousing 108, all as known in the art.

Having thus described the invention, what is claimed 1. Rack and pinionsteering gear for automotive vehicles comprising, a housing having alongitudinal bore of a diameter and a cross bore, a rack guide tubereceived in said longitudinal bore having an outer diameter sorelated tothat of said longitudinal bore as to permit predetermined limited bodilyadjusting movement of said tube within said bore in directions bothradially and tiltably relative to the axis of the latter, injectionmolding passage means defined in said housing and said tube, a rackreceived reciprocably within said guide tube, pinion and pinion shaftmeans received rotatably within said cross bore and meshingly associatedwith said rack so that rotation of said pinion and pinion shaft meanseffects reciprocation of the latter and conthe piston sides whilebuilding up pressure in the other thereof due to restriction from openpassage through one of the return conduits 130. Piston 100 is thuscaused to actuate rack 26 in a corresponding direction. The motivationof valve member 126 in the appropriate direction for such fluid assistin steering takes place by virtue of axial displacement of the pinionshaft and pinion 38' which arises due to the helical teeth thereonmeshing with the complementary teeth of the rack member which isresisted from reciprocation. Accordingly, the end thrust bearingarrangement of the pinion shaft described in the previous embodiment isaltered to permit such relatively free and endwise movement of thepinion and pinion shaft.

The endwise movement of the pinion and pinion shaft, the rod 114 and thecombined valve member 106 in either direction from the neutral conditionshown, is resisted for driver feel by a trapped compression spring 132.One end of such spring bears against a washer 134 cooperable withaligned shoulders in housing 108 and a valve member 106 and the otherend of the spring seats against a washer 136 cooperable with versely,and in situ injection molded retaining means within said passage meansinterconnecting said tube and said housing and holding a radially andtiltably adjusted relationship therebetween.

2. Rack and pinion steering gear for automotive vehicles comprising, ahousing having a longitudinal bore of predetermined diameter and a crossbore, a rack guide tube received in said longitudinal bore having anouter diameter so-related to thatof said longitudinal bore as to permitpredetermined limited bodily adjusting movement of said tube within saidbore radially relative to the axis of the latter, injection moldingpassage means defined in said housing and said tube, a rack receivedreciprocably within said guide tube, pinion and pinion shaft meansreceived rotatably within said cross bore and meshingly associated withsaid rack so that rotation of said pinion and pinion shaft means effectsreciprocation of the latter and conversely, preloading spring meansseated between said housingand said pinion and pinion shaft meansresponsive to radial adjustment of said rack tube within saidlongitudinal bore to exert varying degrees of resilient meshing preloadbetween said rack and said pinion and pinion shaft means, and in situinjection molded retaining means within said passage meansinterconnecting said tube and said housing and holding a radiallyadjusted relationship therebetween.

3. Rack and pinion steering gear for automotive vehicles comprising, ahousing having a longitudinal bore and a cross bore, a rack guide tubereceived for slidable adjustment within said longitudinal housing bore,injection molding passage means in said housing of a limited widthcommunicating with said bore, complementary injection molding passagemeans in the outer surface of said rack guide tube of a width adaptedfor juxtaposition of at least a portion thereof with said housingpassage means over a selected limited range of relatively axiallydisplaced positions between said housing and said tube, a rack memberreciprocably received within said rack tube, pinion and pinion shaftmeans received rotatably within said cross bore and meshingly engagedwith said rack so that rotation of said pinion and pinion shaft meanswill effect reciprocation of the latter and conversely, and in situmolded retaining means within said juxtaposed passage means in saidhousing and said tube holding a selected axially displaced relationshiptherebetween.

4. Rack and pinion steering gear for automotive vehicles comprising, ahousing having a longitudinal bore of predetermined diameter and a crossbore aligned in generally orthogonal planes of said housing, a rackguide tube received slidably in said longitudinal bore and having anouter diameter so related to the diameter of such bore as to permitpredetermined limited bodily movement of said tube within such bore indirections radially of the axis of the latter and also tiltablytherewithin to effect skewing'adjustment between the axis thereof,injection molding passage means in said housing of a limited widthcommunicating with the longitudinal bore thereof, injection moldingpassage means in the outer surface of said rack tube of a width selectedfor juxtaposition of at least a portion of such width with said housingpassage means over a predetermined range of axially slidably displacedpositions between said housing and said tube, arack receivedreciprocably with said tube, pinion and pinion shaft means receivedrotatably within said cross bore of said housing and meshinglyassociated with said rack so that rotation of said pinion and pinionshaft means will effect reciprocation of the latter and conversely, andin situ molded retaining means within said juxtaposed passage means ofsaid housing and said tube holding a selected axial, radial and skewadjusted interrelationship between said housing and said tube.

5. Rack and pinion steering gear for automotive vehicles comprising, ahousing having a longitudinal bore of predetermined diameter and a crossbore, a rack guide tube received in said longitudinal bore having anouter diameter so-relat ed to that of said longitudinal bore as topermit predetermined limited bodily adjusting move ment of said tubewithin said bore radially relative to the. axis of the latter, a rackreceived reciprocably within said guide tube, a pair of shaft bushingsmounted in said cross bore in axially spaced relation and for limitedradial movement therein, pinion and pinion shaft means receivedrotatably within said bushings and meshingly associated with said rackso that rotation of said pinion and pinion shaft means effectsreciprocation of the latter and conversely, and bowed blade spring meansin said housing having a midportion seated on the latter and endportions each seated on a respective said bushing, saidspring meansbeing responsive to said radial adjustment of said tube to flex aboutsaid midportion thereof and effect variable degrees of meshing preloadbetween said rack and said pinion and pinion shaft means.

6. Rack and pinion steering gear for automotive vehicles comprising, ahousing having a longitudinal bore of predetermined diameter and a crossbore aligned in generally orthogonal planes of said housing, a rackguide tube received slidably in said longitudinal bore and having anouter diameter so related to the diameter of such bore as to permitpredetermined limited bodily movement of said tube within such bore indirections both radially of the axis of the latter and tiltablytherewithin to effect skewing adjustment between the axes thereof,injection molding passage means in said housing of a limited widthcommunicating with the longitudinal bore thereof, injection moldingpassage means in the outer surface of said rack tube of a width selectedfor juxtaposition of at least a portion of such width with said housingpassage means over a predetermined range of axially slidably displacedinterrelationships between said housing and tube, a rack receivedreciprocably within said tube, a limitedly radially movable pair ofshaft bushings mounted in said cross bore in axially spaced relation,pinion and pinion shaft means received rotatably within said bushingsand meshingly associated with said rack so that rotation of the saidpinion and pinion shaft means will effect reciprocation of the latterand conversely, bowed blade spring means in said housing having amidportion seated on the latter and end portions each seated on arespective said bushing, said spring means being responsive to saidradial adjustment of said tube transferred through corresponding motionof said bushings and pinion and pinion shaft means to exert varyingdegrees of resilient tooth meshing preload force between said rack andsaid pinion and pinion shaft means, and in situ molded retaining meanswithin said juxtaposed passage means of said housing and said tubeholding a selected axial, radial and skew adjusted interrelationshipbetween said housing and said tube.

7. In a method of assembling a rack and pinion steering gear of a typeincluding a housing having a longitudinal rack bore and a cross bore fora pinion shaft, further including a rack guide tube receivable withinthe housing longitudinal bore and in turn receiving a rack memberslidable therewithin, said housing and said rack guide tube beingprovided with injection molding passage means for effecting retention ofa selected interrelationship between said housing and said tube, thesteps comprising, inserting said rack tube within said longitudinal boreof said housing and said rack member within said tube, adjusting theposition of said rack member axially of said tube relative to said crossbore so as to effect a generally equal amount of available reciprocationof said rack relative to said tube from said adjusted position in eitherdirection therefrom, inserting a pinion-and pinion shaft assembly withinsaid cross bore and into meshing engagement with said rack in theadjusted position of the latter, adjusting said rack tube within thelongitudinal bore of said housing in directions both radially andtiltably therewithin for adjusting the meshing relation between thepinion and the rack, and injecting in situ. moldable material withinsaid housing and rack tube passage means to hold said adjustedrelationships of said parts of the gear upon curing thereof.

8. In a method of assembling a rack and pinion steering gear of a typeincluding a housing having a longitudinal rack bore and a cross bore fora pinion shaft, further including a rack guide tube receivable withinthe housing longitudinal bore and in turn receiving a rack memberslidable therewithin, said housing and said rack guide tube beingprovided with an injection molding passage means for effecting retentionof a selected interrelationship between said housing and said tube, thesteps comprising, inserting said rack tube within said longitudinal boreof said housing and inserting said rack member within said tube,adjusting the position of said rack member axially of said tube relativeto said cross bore so as to coarsely effect a generally equal amount ofavailable reciprocation of said rack relative to said tube from saidadjusted position in either direction therefrom, inserting a pinion andpinion shaft assembly within said cross bore and into meshing engagementwith said rack in the adjusted position of the latter, adjusting saidrack tube within the longitudinal bore of said housing in directionsboth radially and tilting thereof.

1. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore of a diameter and a cross bore, a rack guide tube received in said longitudinal bore having an outer diameter so-related to that of said longitudinal bore as to permit predetermined limited bodily adjusting movement of said tube within said bore in directions both radially and tiltably relative to the axis of the latter, injection molding passage means defined in said housing and said tube, a rack received reciprocably within said guide tube, pinion and pinion shaft means received rotatably within said cross bore and meshingly associated with said rack so that rotation of said pinion and pinion shaft means effects reciprocation of the latter and conversely, and in situ injection molded retaining means within said passage means interconnecting said tube and said housing and holding a radially and tiltably adjusted relationship therebetween.
 2. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore of predetermined diameter and a cross bore, a rack guide tube received in said longitudinal bore having an outer diameter so-related to thatof said longitudinal bore as to permit predetermined limited bodily adjusting movement of said tube within said bore radially relative to the axis of the latter, injection molding passage means defined in said housing and said tube, a rack received reciprocably within said guide tube, pinion and pinion shaft means received rotatably within said cross bore and meshingly associated with said rack so that rotation of said pinion and pinion shaft means effects reciprocation of the latter and conversely, preloading spring means seated between said housing and said pinion and pinion shaft means responsive to radial adjustment of said rack tube within said longitudinal bore to exert varying degrees of resilient meshing preload between said rack and said pinion and pinion shaft means, and in situ injection molded retaining means within said passage means interconnecting said tube and said housing and holding a radially adjusted relationship therebetween.
 3. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore and a cross bore, a rack guide tube received for slidable adjustment within said longitudinal housing bore, injection molding passage means in said housing of a limited width communicating with said bore, complementary injection molding passage means in the outer surface of said rack guide tube of a width adapted for juxtaposition of at least a portion thereof with said housing passage means over a selected limited range of relatively axially displaced positions between said housing and said tube, a rack member reciprocably received within said rack tube, pinion and pinion shaft means received rotatably within said cross bore and meshingly engaged with said rack so that rotation of said pinion and pinion shaft means will effect reciprocation of the latter and conversely, and in situ molded retaining means within said juxtaposed passage means in said housing and said tube holding a selected axially displaced relationship therebetween.
 4. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore of predetermined diameter and a cross bore aligned in generally orthogonal planes of said housing, a rack guide tube received slidably in said longitudinal bore and having an outer diameter so related to the diameter of such bore as to permit predetermined limited bodily movement of said tube within such bore in directions radially of the axis of the latter and also tiltably therewithin to effect skewing adjustment between the axis thereof, injection molding passage means in said housing of a limited width communicating with the longitudinal bore thereof, injection molding passage means in the outer surface of said rack tube of a width selected for juxtaposition of at least a portion of such width with said housing passage means over a predetermined range of axially slidably displaced positions between said housing and said tube, a rack received reciprocably with said tube, pinion and pinion shaft means received rotatably within said cross bore of said housing and meshingly associated with said rack so that rotation of said pinion and pinion shaft means will effect reciprocation of the latter and conversely, and in situ molded retaining means within said juxtaposed passage means of said housing aNd said tube holding a selected axial, radial and skew adjusted interrelationship between said housing and said tube.
 5. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore of predetermined diameter and a cross bore, a rack guide tube received in said longitudinal bore having an outer diameter so-related to that of said longitudinal bore as to permit predetermined limited bodily adjusting movement of said tube within said bore radially relative to the axis of the latter, a rack received reciprocably within said guide tube, a pair of shaft bushings mounted in said cross bore in axially spaced relation and for limited radial movement therein, pinion and pinion shaft means received rotatably within said bushings and meshingly associated with said rack so that rotation of said pinion and pinion shaft means effects reciprocation of the latter and conversely, and bowed blade spring means in said housing having a midportion seated on the latter and end portions each seated on a respective said bushing, said spring means being responsive to said radial adjustment of said tube to flex about said midportion thereof and effect variable degrees of meshing preload between said rack and said pinion and pinion shaft means.
 6. Rack and pinion steering gear for automotive vehicles comprising, a housing having a longitudinal bore of predetermined diameter and a cross bore aligned in generally orthogonal planes of said housing, a rack guide tube received slidably in said longitudinal bore and having an outer diameter so related to the diameter of such bore as to permit predetermined limited bodily movement of said tube within such bore in directions both radially of the axis of the latter and tiltably therewithin to effect skewing adjustment between the axes thereof, injection molding passage means in said housing of a limited width communicating with the longitudinal bore thereof, injection molding passage means in the outer surface of said rack tube of a width selected for juxtaposition of at least a portion of such width with said housing passage means over a predetermined range of axially slidably displaced interrelationships between said housing and tube, a rack received reciprocably within said tube, a limitedly radially movable pair of shaft bushings mounted in said cross bore in axially spaced relation, pinion and pinion shaft means received rotatably within said bushings and meshingly associated with said rack so that rotation of the said pinion and pinion shaft means will effect reciprocation of the latter and conversely, bowed blade spring means in said housing having a midportion seated on the latter and end portions each seated on a respective said bushing, said spring means being responsive to said radial adjustment of said tube transferred through corresponding motion of said bushings and pinion and pinion shaft means to exert varying degrees of resilient tooth meshing preload force between said rack and said pinion and pinion shaft means, and in situ molded retaining means within said juxtaposed passage means of said housing and said tube holding a selected axial, radial and skew adjusted interrelationship between said housing and said tube.
 7. In a method of assembling a rack and pinion steering gear of a type including a housing having a longitudinal rack bore and a cross bore for a pinion shaft, further including a rack guide tube receivable within the housing longitudinal bore and in turn receiving a rack member slidable therewithin, said housing and said rack guide tube being provided with injection molding passage means for effecting retention of a selected interrelationship between said housing and said tube, the steps comprising, inserting said rack tube within said longitudinal bore of said housing and said rack member within said tube, adjusting the position of said rack member axially of said tube relative to said cross bore so as to effect a generally equal amount of available reciprocation of said rack relative tO said tube from said adjusted position in either direction therefrom, inserting a pinion and pinion shaft assembly within said cross bore and into meshing engagement with said rack in the adjusted position of the latter, adjusting said rack tube within the longitudinal bore of said housing in directions both radially and tiltably therewithin for adjusting the meshing relation between the pinion and the rack, and injecting in situ moldable material within said housing and rack tube passage means to hold said adjusted relationships of said parts of the gear upon curing thereof.
 8. In a method of assembling a rack and pinion steering gear of a type including a housing having a longitudinal rack bore and a cross bore for a pinion shaft, further including a rack guide tube receivable within the housing longitudinal bore and in turn receiving a rack member slidable therewithin, said housing and said rack guide tube being provided with an injection molding passage means for effecting retention of a selected interrelationship between said housing and said tube, the steps comprising, inserting said rack tube within said longitudinal bore of said housing and inserting said rack member within said tube, adjusting the position of said rack member axially of said tube relative to said cross bore so as to coarsely effect a generally equal amount of available reciprocation of said rack relative to said tube from said adjusted position in either direction therefrom, inserting a pinion and pinion shaft assembly within said cross bore and into meshing engagement with said rack in the adjusted position of the latter, adjusting said rack tube within the longitudinal bore of said housing in directions both radially and tiltably therewithin for adjusting the meshing relation between the pinion and the rack axially displacing said tube relative to said rack and said housing to effect a fine adjustment for a fairly precisely equal amount of said available rack reciprocation in either direction, and injecting in situ moldable material within said housing and rack tube passage means to hold said adjusted relationships of said parts of the gear upon curing thereof. 